Sean Welsh fired Inverness Caledonian Thistle to another Scottish Cup shock and leave Premiership strugglers Kilmarnock out in the Scottish Cup cold.
A penalty from Billy McKay and a second-half strike by class act Welsh wiped out Kyle Vassell's early opener to send Caley through to the semi-finals of a competition they won eight years ago.
But it is now four games without a win for Killie whose hopes of reaching the last four were extinguished by a team sitting mid-table in the Championship.
Derek McInnes' men will now have to regroup for a grim battle against relegation from the top flight as Caley set the sat-nav for Hampden and use this win to mount a late play-off run.
Kilmarnock got off to the perfect start in the Highland capital with the opening goal after just three minutes.
Dan Armstrong delivered a wicked corner with pace which was flicked on by Liam Donnelly for Vassell to touch the ball home from close range.
But the home side took the game to their top-tier opponents and only an instinctive save by keeper Sam Walker denied McKay after a clever ball into the area from midfield maestro Welsh.
In the 23rd minute, Inverness came closer still when on-loan St Mirren midfielder Jay Henderson whipped in a cross for Welsh whose header grazed the bar.
Caley eventually equalised three minutes later. Killie defender Joe Wright awkwardly stretched to clear a Wallace Duffy cross but only succeeded in hittng the ball against his own arm.
As he was in the box, referee David Dickinson awarded a penalty with McKay's resulting low effort squirming through keeper Walker's legs.
On the half-hour mark, Henderson sprinted clear and had a glorious chance to make it 2-1 but his shot was blocked by Walker.
The East Ayrshire side had plenty of work to do as the second half began but within five minutes of the restart they were behind.
Henderson was involved again, drilling in a cross from the right which was cleared by Lewis Mayo as far as Welsh whose low shot flew under Walker and into the net.
Inverness fans were jubilant as television replays showed Walker should have done much better when Welsh took aim from 25 yards.
McInnes' men were now in deep trouble in the frozen north and there wouldn't have been many among the dedicated travelling support confident the team would pull through for them, given their dreadful away record all season.
The signs were not encouraging as, despite McInnes ringing the changes, Killie were unable to create clearcut chances as the Caley defence soaked up the pressure and kept the game in front of them.
With a minute remaining, Inverness launched a counter attack. Substitute Austin Samuels was bearing down on goal with Jeriel Dorsett in hot pursuit and the Killie defender did just enough in the end as the striker's shot lacked power and was gathered by Walker.
There were four minutes of injury time but Killie never looked like taking the tie to extra time and a new low was endured in this disappointing of campaigns.
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